Antifoggant for photographic developers and solubilizing agent for hydrazines



' June 30, 1959 M. l-:UNSBERGER 2,892,715

ANTIFOGGANT FOR PHOTOGRAPHIC DEVELOPERS AND SOLUBILIZING AGENT EOE HYDRAEINES Filed Nov. l5, 1955 3 Sheets-Sheet l ATTORNEYS.

June 30, 1959 l. M. HUNsBl-:RGER 2,892,715

ANTIFOGGANT FOR PHOTOGRAPHE@ DEVELOPERS AND SOEUEILIZING AGENT FOR HYDRAZINES Filed Nov. l5, 1955 3 Sheets-Sheet 2 BY M v ATTO R NEYS.

June 30, 1959 l. M. HUNSBERGER 2,892,715

ANTIFOGGANT FOR PHOTOGRAPHIC DEVELOPERS AND SOLUBILIZING AGENT FOR HYDRAZINES Filed Nov. l5, 1955 ."5 Sheets-Sheet 5 A l X 1o zo f- .Srocx .Saur/olv IN V EN TOR. .[3446 /570 ref Hwascff MNM United States Patent lANTIFGGANT FOR PHOTOGRAPHIC DEVEL- OPERS AND SOLUBILIZING AGENT FOR HY- DRAZINES Application November 15, 1955, Serial No. 546,958

' 5 Claims. (Cl. 96-66) This invention relates to antifoggants for photographic developers and solubilizing agents for hydrazines, and is a continuation-impart of my copending application Serial No. 440,635, tiled July 1, 1954, now abandoned. In recent years it has been found that various substances, and particularly hydrazines and various hydrazine de rivatives, can be added to conventional photographic developers and particularly photographic developers of the high alkali metol hydroquinone type with the result of greatly increasing the speed of the particular iilm which is developed in such a developer. It has also been found that this advantage is accompanied by a corresponding disadvantage in that the fog density is also increased. Furthermore, many arylhydrazines and substituted arylhydrazines are so insoluble in the devleopers that their utility is seriously impaired.

This increased fog density can be reduced to acceptable l limits while maintaining a significant increase in film speed by adding to the developer a conventional antifogging agent. Such antifogging agent may be, for example, 6-nitrobenzimidazole nitrate and such antifogging agent will reduce the fog density to tolerable limits but the use of such a conventional antifogging agent also often produces quite a considerable increase in the gamma orcontrast of the negative. Now some hydrazines, when added to photographic developers, also have the effect of increasing the gamma and if the above mentioned antifoggant is used with developers containing hydrazines of the type just referred to, the increase in gamma above the control becomes very large and is undesirable in some practical applications.

With the above considerations in mind, it is an object of the present invention to provide an antifoggant which may be added to the conventional high alkali metol hydroquinone developers which also contain hydrazine or a hydrazine derivative and which will reduce fogging to acceptable limits without the accompanying increase in gamma.

f Another object is to provide a method of solubilizing the less soluble hydrazines in photographic developers, so that the range of utility of the hydrazines may be increased.

These and other objects of theinvention which will be pointed out in more detail hereinafter or which will become apparent to one skilled in the art upon reading these specifications, I accomplish by that series of steps and by that composition of matter of which I shall now describe an exemplary embodiment. Reference is made to the accompanying drawings in which:

Figure 1 is a graph of speed plotted against concentration of antifoggant showing ya comparison between the antifoggant of the present invention and a conventional antifoggant.

Figure 2 is a similar graph but plotting fog density 'against concentration, and Figure 3 is a similar graph but plotting `concentration.

ICC

Briefly, in the practice of my invention, I add to the developer two commercially available surfactants: sodium xylene sulfonate (Naxonate G) and active octyl phenoxy polyxyethylene ethanol (Igepal CA-630). Naxonate G is a product of Wyandotte Chemicals Corporation, and lgepal CA-630 is a product of the General Aniline and Film Corporation. Hereinafter these substances in combination will be referred to as the new AF. I have found that when the new AF is added to a developer such as D19 containing a hydrazine, the gamma may be held very close to the control value while maintaining a signiicant increase in lmspeed. The new AF functions as above outlined when used with D19 containing hydrazine or its derivatives such as, for example, 4-bromo-l-naphthylhydrazine and o-ethylphenylhydrazine.

A typical high alkali metol hydroquinone type developer is Eastman Kodak Company D-l9 which has the following formula:

Grams Elon 2.2 Sodium sulte (desiccated) 96.0 Hydroquinone 8.8 Sodium carbonate (monohydrated) 56.0 Potassium bromide 5.0

Water to make 1 liter.

In Figures 1, 2 and 3 one milliliter of the stock solution of the new AF contains 0.025 milliliter of Igepal CA-630 and 0.30 milliliter of a 40% aqueous solution of Naxonate G.

The 1 l06 molar solution of 4-bromo-l-naphthylhydrazine in D-19 developer is prepared by slurrying 0.0011 g. of the hydrazine in 10 drops of Igepal CA-630, dissolving the slurry in 50 ml. of 40% Naxonate G solution, diluting to 1 liter with distilled water, and finally adding 3 liters of strength D-19. The strength developer of course contains four-thirds the amount of the ingredients in the table above, in one liter of water. This procedure produces 4 liters of D-19 developer containing the above hydrazine at a concentration of 1 106 molar. This process is necessary because the above hydrazine is virtually insoluble in plain D-19 developer. The combination of NaXonate G and Igepal CA-630 serves as a much better solubilizing agent than Naxonate G alone. The uniqueness of this solubilizing effect is evident by the fact that a large number of other commercially available surfactants either failed to show this solubilizing eifect or exhibited the eiect to only an inconsiderable degree. By varying the amounts of Igepal CA-630 and Naxonate G used, a large number of other wise insoluble arylhydrazines and substituted arylhydrazines can be dissolved in photographic developers. That the Naxonate G and Igepal CA-630 are also antifoggants is a decided advantage in practical work. Concentrations of at least as high as 16.5 ml. of Igepal CA-63O and ml. of 40% Naxonate G per liter are tolerated by D19 containing a hydrazine, but seldom are such large quantities required for solubilizing hydrazines.

This solubilizing procedure therefore greatly extends the range of concentrations of the less soluble hydrazines that can be achieved in photographic developers. The hydrazine (or its hydrochloride salt) dissolves most easily by rst thoroughly wetting the solid with the Igepal (3-40 drops) and then adding the 40% Naxonate G solution (5-400 m1,). Finally dilute to 1 liter with distilled water and add 3 liters of 4/3 strength D-l9. This gamma against v procedure makes 4 liters of developer, and the hydrazines often can be present at concentrations as high as 0.01- 0.02 molar. The use of various hydrazines in developers for the purpose of increasing emulsion speed has already been mentioned. i

Referring now to the drawings, in Figure 1 hlm speed is plotted against concentration of antifoggants and in this gure there is shown the effect of the new AF, i.e. Naxonate G and Igepal CA-630, as compared with the effect of a conventional antifoggant, in this instance 6- nit-robenzimidazole nitrate which is referred to hereafter as AF #2. One set of curves relates to the effects found with plain D-19 developer, another set to the elects found with D-19 containing each antifoggant, and the third set relates to the effects found with D-19 developer containing 4-bromo-1-naphthylhydraz'inel-ICI and each of the antifoggants. From these curves it will be observed that as the concentration of AF #2 in D-19 increases, the speed soon decreases and continues to decrease steadily, whereas the new AF produces no `significant change in film speed at any concentration listed.

In the case of the D-19 containing 4-bromo-l-naphthylhydrazine in a concentration of 1 106 molar, addition of AF #2 produces a rapid increase in speed up to a concentration of about .00022 M and then a very rapid drop. The curve crosses the control line at a concentration of about .00055 M and continues to drop thereafter. On the other hand, with the new AF there is a slight increase in speed up to about 10 ml. per liter followed by aV decrease in speed at a slower rate than was encoun-- tered with AF #2, leveling olf yat a concentration of about 30 ml. per liter, at which point it is still well above the control speed.

In Figure 2, I have similarly compared the effect with and without the above hydrazine of AF #2 and the new AF plotting fog density against concentration.

In D-19, addition of AF #2 is accompanied by a decrease in fogvdensity. With the new AF, the decrease in fog density is slower to appear and never becomes as large.

In D-19 which has been treated with 4-bromo-1-naphthylhydrazine, the AF #2 curve drops rapidly with an increase in concentration and the curve has dropped below the control by the time a concentration of .00033 M has been reached. The curve levels off at a concentration of about .00066 M and roughly coincides with the curve for D19 containing only AF #2. With the new AF, there is also a drop in fog density with an increase in concentration and the curve crosses the control line at about 25 rnl. per liter and remains only slightly below it at higher concentrations.

Coming now to Figure 3 wherein gamma is plotted against concentration of antifoggants and considering D- 19 containing AF #2, it will be noted that gamma rst drops as concentration increases, then rises rapidly to a concentration of .00055 M and then drops more slowly, although remaining well above the control line. As distinguished from this, the new AF produces a curve which drops gradually with an increase in concentration up to about r'nl. per liter and then remains fairly level up to a concentration of about 40 ml. per liter.

With D-19 containing 4-bromo-1-naphthylhydrazine at a concentration of 1x10*6 M, the conventional antifog'- gant produces' a rapid increase in gamma with an increase in' concentration leveling olf, at a concentration of about .00077 M, well above the control line. The gamma curve crosses the control line at a concentration of about .00044 M. On the other hand, the new AF brings about an increase in gamma at a slower rate than AF #2 and the curve levels off at a concentration of about 35 ml. per liter but remains well below the control.

From the foregoing discussion and from a consideration of theV figures herein, it is apparent that the new AF gives a greater flexibility in regard to the concentration required to produce a' particular hlm speed and fog density. One of the disadvantages of the conventional antifoggant, when used in D-19` containing certain' hydrazines, is that seemingly trivial changes in the amount of antifoggant used often produce great changes in film speed' and fog density. It is also apparent from what has gone before that the new AF produces lower gamrn'as than the conventional antifoggant and this is advantageous in some practical applications.

Also, the new AF improves the bad grain characteristically produced on the emulsion by certain hydrazines, e.g. 1-chloro-Z-naphthylhydrazine.

The concentration of the new AF required to completely 'destroy the fog and speed increasing effect of the hydrazine in D-19 developer Varies with the concentration of the particular hydrazine.

It will also be understood from a study of the iigures that the gammas may b'e controlled by combining the new AF with AF #2 in various proportions. As with the conventional antifoggant, a stock solution of the new AF may be prepared for convenience in adding known quantities of the antifoggant tothe developer.

The new AF can be used as the sole antifoggant in D- 19 containing hydrazine or its derivatives. Furthermore, proper adjustment of the concentration of the new AF will enable roughly `the same increases in film speed to b e obtained as is the case when AF #2 is used as the sole antifoggant. v Y l I i Generally speaking, the new AF does not produce the large increase in gamma characteristic of AF #2.. Fur-` thermore, the concentration of the new AF required to produce a certain fog level is more exible than is the case with AF #2. As pointed outabove also combinations of the two antifoggants make it possible to obtain a. wide range of gammas. p v p Since 4-bromo-l-naphthylhydrazine requires the use of considerable quantities `of Igepal CA-630 and NaXonate G in order to render the hydrazine soluble thedeveloper, the action of my new AF was testedagainst ,o-

ethylphenylhydrazine, which is soluble in plain D-19 developer. l Y l n 'I he results= of one series of tests are summarized in Table l, which' lists the percentage of the original hydra- Zine fog that remains at 8, 12, and 18 minutesrdevelop.- ment when various quantities of the new AF are present. The o-ethylphenylhydrazine was used at a concentration of 0.0001 M in .D-V19 developer, and in all cases (errcept :thosedesignated by asterisks) ml. of 40% aqueous Naxonate G was present per liter of D-l9 developer.

Table 1 A Development Time ml. of Igepal (3A-630 per liter of D-19 8 min. 12 mln. 18 ruin.

Percent Percent Percent 77. 77. 0 83.3 57. 4 65.8 74. 1 60. 6 68. 2 73. 8 51. s 5 0. 4 57.7 45.9 43.9 49. 0 41.0 39. 5 43. 7 39. 2 43, Q 45. a 33. 5 36. 4 40. 2 28. 2 33. 4 38. 1 16. 6 18.1 25. 0 15. o 17. e 22; 7 15. 5 17. 6 23. 5

106'` ml. 40% Naxonate G per liter of D-19. 112 m1. 40% N axonate G per liter of D-19.

From this table it is apparent that on a volume the Igepal CA-630 is a much more potent antifogg'ant than the Naxonate G. Furthermore the first .portions of the IgepalA CA-630 are more eective than the last portion's. The Naxonate G is required in order to keep the Igepal in solution. Up to 16.5 vml. (andpossibly more) Igepal will stay inr solution in 1 liter of D-19 containing a hydrazine if `115 ml. of 40% Naxonate G is added immediately. If 10-20 minutes elapses between adding the Igepal and the Naxonate, a black oily sub- Stance forms. Although this substance dissolves on adding more Naxonate G, the resulting developer solution has an undesirable dark color. Even the largest of the above-mentioned quantities of Naxonate G and Igepal CEA-630 have no undesirable etfect on the emulsion. Instead, the emulsion graininess produced by certain hydrazines is considerably improved by the Naxonate G and Igepal CA-630.

Having now fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An alkaline photographic developer containing pmethyl aminophenol sulphate and hydroquinone, to which there has vbeen added, for the purpose of increasing lm speed, a member of the group consisting of hydrazine and an aqueous insoluble arylhydrazine, containing, as an antifoggant, sodium xylene sulfonate and octyl phenoxy polyoxyethylene ethanol.

2. An alkaline photographic developer containing pmethyl aminophenol sulphate and hydroquinone to which there has been added, for the purpose of increasing lm speed, a member of the group consisting of hydrazine and an aqueous insoluble arylhydrazine, containing, as an antifoggant, t-nitrobenzimidazole nitrate with sodium xylene sulfonate and octyl phenoxy polyoxyethylene ethanol.

3. A method of developing exposed light sensitive photographic emulsions while reducing fog density and without unduly increasing the gamma which comprises developing the said emulsion with an alkaline photographic developer containing p-methyl aminophenol sulphate and hydroquinone, to which there has been added, for the purpose of increasing lm speed, a member of the group consisting of hydrazine and an aqueous insoluble arylhydrazine, containing, as an antifoggant, sodiutiixyllene sulfonate and octyl phenoxy polyoxyethylene e ano 4. A method of developing exposed light sensitive photographic emulsions while reducing vfog density and without unduly increasing the gamma which comprises developing the saidemulsion with an alkaline photographic developer containing p-methyl aminophenol sulphate and hydroquinone, to which there has been added, for the purpose of increasing lm speed, a member of the group consisting of hydrazine and an aqueous insoluble arylhydrazine, containing, as an antifoggant, 6-nitrobenzimidazole nitrate with sodium xylene sulfonate and oetyl phenoxy polyoxyethylene ethanol.

5. A method solubilizing a hydrazine compound from the group consisting of hydrazine and an aqueous insoluble arylhydrazine, in an alkaline photographic developer, which comprises the steps of slurrying said hydrazine compound in octyl phenoxy polyoxyethylene ethanol, dissolving the slurry in a aqueous sodium xylene sulfonate solution, diluting the resulting solution with distilled water and adding the diluted solution to an aqueous alkaline solution of p-methyl aminophenol sulphate and hydroquinone.

References Cited in the tile of this patent FOREIGN PATENTS Great Britain Apr. 2, 1952 

1. AN ALKALINE PHOTOGRAPHIC DEVELOPER CONTAINING PMETHYL AMINOPHENOL SULPHATE AND HYDROQUINONE, TO WHICH THERE HAS BEEN ADDED, FOR THE PURPOSE OF INCREASING FILM SPEED, A MEMBER OF THE GROUP CONSISTING OF HYDROZINE AND AN AQUEOUS INSOLUBLE ARYLHYDRAZINE, CONTAINING, AS AN ANATIFOGGANT, SODIUM XYLENE SULFONATE AND ACTYL PHENOXY POLYOXYETHYLENE ETHANOL. 